[Buildroot] [PATCH 1/1] rust: make sure the cxx compiler is also set for the target

[Thomas Petazzoni]

Hello,

[Side note: it is customary on open-source mailing list to avoid
 top-posting, and instead reply below the text you are replying to.
 Thanks!]

On Sun, 1 Apr 2018 23:05:11 +0000, Charles Hardin wrote:

> Oh, I think I might remember the problem on TARGET - HOST, notice the core_avx2
> is our target and our buildslaves don’t have avx2 and rust has some stage where it
> built a local tool and it didn’t run on the buildslave because it used the cross compiler

Well, that's a severe bug. If Rust uses the cross-compiler to build a
program that it then runs on the host, this is not going to work on a
number of situations. Your defconfig uses glibc for the target, and
your host most likely uses glibc as well, so there are some chances
that a tool built with the cross-compiler will also run on the host.
But if the CPU optimization options are different (like you had with
AVX2) or the C library is different than glibc, then the tool built
with the cross-compiler will definitely not run on the host.

However, we do have a x86-64 uClibc configuration in our autobuilders,
which is built on a x86-64 machine, and I don't think we have seen any
issue. So, I'm a bit puzzled.

Which specific internal tool was causing the problem ?

Thanks,

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com